Irradiating device



Jan. 19, 1932.

N. K. CHANEY IRRADIATING DEVICE Filed April ll. 1928 2 Sheets-Sheet l r l i. ll I. .l.||||| Jan. 19, 1932.

N. K. cHANEY v 1,842,313

IRRADIA'TING DEVICE Filed April 1l. 19.28 2 Sheets-Sheet 2 A T TORNEYS.

d Patented Jan. 19., 1932 UNITED STATES PATENT GFFICE NEWOOMB x. OHANE'Y, OF cLnvnLANn, OHIO, AssIGNon 'ro NATIONAL cAmaON GOM- PANY, INO., A CORPORATION or NEW YORK IRRADIATING DEVICE Application med April 11, 1928. Serial No. 2695248.l

gA the type usually known as ultra-violet.

As is well known ultra-violet radiation is effective in producing certain changes on various substances. Thus it has been found that when certain food studs are irradiated with ultra-violet energy the vitamin content is increased, especially with regard to vitamin D. Examples of such food stuffs are various forms of cereal products such as are used for so-called breakfast foods. Also this type of radiated energy is effective in killing certain bacteria such as the bacteria which cause souring of milk as well as pathogenic bacteria. Thus milk may be irradiated with ultra-violet energy as a substitute for pasteurization, and also to increase its vitamin content. Because of the difficulties encountered it is imperative that this irradiation be performed eliciently. The radiation which lies in the region of the photochemically active wave lengths, e. g. from about 220 to 320 millimicrons7 is only a small percentagefor the carbon arc. This places a tremendous premium' on the complete utilization of the radiation ofthe desired wave lengths actually generated. Also the problem of utilizing these small percentages' of radiant energy of the required wave lengths is much more diliicult than is the case with the corresponding visible and infra red radiation due to the high absorption coeflicients shown for these short j wave-lengths by most reflectors and by most transparent screen materials. Also the short -vvave-radiations are readily absorbed by dust I most efiioient as generators of ultra-violet also produce the greatest quantities of fumes and 'lparticles, by certain gases and by grease films. 40

It is` desirable that the carbon arc be separatedpby a, screen from the materialto he treated. However the flame arcs which are corrosive .gases which promptly foul and destroy the transparency of the enclosing Because of the great losses incident to any attempt to reflect ultra-violet energy and furthermore because ofthe impossibility of securing uniform distribution of such energy le plane upon such material moving in a sin I have found it desirable to mount tide source of energy in the axis of a surface of revolution, as a sphere or cone, the material to be irradiated passing along said surface. Such an arrangement has the following advantages: 4

Uniform irradiation of all materials {iowing on the interior of said surface is secured because the photometric distribution curve of such an arc is radially symmetrical.

Primary reflectors are unnecessary since all of the radiationfalls directly on the surfaces over. which the irradiated material must pass. y

The .surface and irradiated material act as a secondary reflector for any stray energy not absorbed by direct irradiation and such refiected energy is in turn uniformly distributed to all parts of said surface in accordance with the well known principles'of the integrating photometer.

An object of my inventiony is toprovide a. device in which this irradiation may be car ried out simply and efficiently. Another object of my invention is to provide a device in which the substance to be treated is so agitated during passage through my device that all parts of the substance will be exposed to the influence of the radiation. Another object of my invention is to provide means for cutting ofi deleterious radiation such as heat and to provide means for lkeeping the screen surrounding the source of radiation clean.

These and other objects of my invention will be evident from the following description having reference to the accompanying drawings in which l Figure 1 is a vertical sectional view through a device illustrating one embodiment of my invention and Figure 2 is a vertical sectional view through a device illustrating another embodiment of my invention.

In Figure 1, I show an irradiating chamber 10 which is preferably in the form of va sphere, although I do not wish to limit myself solely to the use of a sphere. At the upper and lower ends of the sphere are pairs cylinders 13 and 14 is closed by means of a copending similar closure 17 and a conduit 18 is provided for carrying away the Huid which has collected therein. Between the cylinders 11 and 13 I provide a screen 19 of a substance which permits the passage of a`large proportion of the energy radiated therein. In case the energy is of the ultra-violet type this screen would ordinarily be made of quartz or of vspecial ultra-violet transmitting glasses. In .the interior of the cylinders 12 and 14, I provide means for supporting the source of energy which is preferably an arc lamp having electrodes which emit a large amount of ultraviolet radiation. While I do not limit myself to the use of any particular type of electrodes, I have found that carbon electrodes having a core containing nickel, aluminum and iron together with carbon and a binder are well suited for this purpose. Examples `of such carbons are those described in the application of M. J. Dorcas, Serial No. 222,854, filed September 24, 1927. A liquid is introduced in the conduit 15 and flows down between the cylinders 11 and 12,

. means being provided for spraying the liquid on the inner surface of the screen 19. A convenient method of effecting this spraying consists in providing the cylinder 11 with a number of small holes slightly above the closure 16. The liquid Hows down over the inner surface of the screen, thence between the y cylinders 13 and 14 and out the conduit 18. The liquid serves to keep the inner surface of the screen clean from the fumes of metal oxides given ofi by the arcs, by which they would otherwise be quickly fouled and also acts as a filter for cutting ofi' certain obj ectionable radiations. While I may employ various types of liquids, I have found that distilled water is satisfactory in many cases as this cuts oif some of the radiated heat without interfering with the ultra-violet radiations. Anyfumes generated by the arc lamp are conducted away through the cylinder 12. In case the lsubstance to be irradiated is a liquid, it is introduced through a conduit 21 which passes through the upper part of the sphere and is distributed over the inner surface of this sphere by nozzles 22-22. The liquid thus introduced flows down over the inner surface ofthe sphere in a thin film and receives the emanations from the source of radiant energy. The inner surface of the sphere may be coated with a substance which reflects the radiated energy. Thus if any portion of the inner surface is not covered by liquid being treated, the radiation will be surfaces I have found that type consisting of particles of silicon embedded in a suitable binder to be very satisfactory. The liquid after being irradiated collects at the bottom of the sphere and is carried away by conduit 23. In order to minimize heating, I provide means for circulating neutral gas through thc sphere such means comprising condults 24 and 25. It will of course be evident that in case I wish to'irradiate gas I may pass the gas through the irradiating 4chamber by means of these conduits, in which casel the conduits 21 and 23 would be closed.

In Figure 2 I show another device illustrating a further embodiment of my invention. This device is especially adapted for the use in treating finely divided solid materials such as cereal food products. In this kdevice I show a chamber 31 in the shape of an inverted cone, the walls of the cone being provided with ridges 32 to tumble the material as it falls downwardly under the force .of gravity. The chamber is provided with the pairs of concentrically arranged cylinders liquid supply 15 is shown in Figure 1. The upper part of the chamber is provided with a hopper 33 through which the material to be treated is introduced. At the bottom of the chamber is a conduit 34 through which the treated material is removed. In case it is desired to keep the material to be treated in a neutral gas, this gas is introduced through a conduit 24 and removed through a conduit 25 as in Figure 1. In this case the flow of the material through the conduit 33 and 34 is so regulated that an accumulation of the material itself acts as a seal to prevent the admission of air into the irradiating chamber. At the top of the chamber and surrounding the cylinder 11, a rotatable member 35 is mounted in any suitable manner, such as by the ball bearings 36 and 37: This is caused to rotate in any suitable manner as by a worm .38 engaging a worm wheel 39 secured to the rotatable member 35. This member carries near its lower end a distributing plate 41 which conveys the material to be treated from the conduit 33 and distributes it around the surface of the cone whence it falls downwardly, being tumbled in passing over the ridges 32. Operatively connected to the rotatable member 35 is a brush 42 which serves to remove material from the outer surface of the screen 19 where it would otherwise cut down the amount of energy available for irradiating the material passing through the chamber.

I claim:

1. An irradiating device comprising a chamber, an arc lamp within said chamber, a screen surrounding sai dare lamp and transmitting a high proportion of the violet and -ultra-violet energy, a pair of tubes extending from said screen through the upper part of said chamber, the space between said tubes being closed near their lower end, means for supporting said arc lamp within said inner tube and means near the lower end of said tubes for directinga stream of liquid against the inner surface of said screen.

2. A device as claimed in claim l in which said chamber is a stepped cone.

3. A device as claimed in claim l in which the inner surface of said chamber is coated with silicon.

4. An irradiating device comprising a chamber, means for supplying material to be treated to said chamber, a source of radiant energy within said chamber, a screen surrounding said source of energy, means for distributing the material to be treated around said chamber and means carried by said distributing means for mechanically removing ldeposited material from said screen.

5. An irradiating device comprising a source of ultra-violet energy, a quartz screen surrounding said source of energy, a chamber surrounding said screen, means for passing a liquid along the inner surface of said screen, means for passing a substance to be treated through said chamber, and reflecting means on the walls of said chamber comprisi ing a liningof silicon.

6. An irradiating device comprising an arc lamp containing flame carbon electrodes, a quartz screen surrounding said arc lamp, a chamber surrounding said screen, means for passing a food stuif through said chamber, a mechanically operated distributing plate and rotating means, means comprising a source of liquid and a distributor for covering the inner surface of said screen with awashv ing uid, and mechanical means for removing food stuffs from the exterior surface of said screen.

7. An irradiating device comprising an arc lamp containing flame carbon electrodes, a quartz screen surrounding said arc lamp. a chamber surrounding said screen, means for passing a food stuff through said chamber, a mechanically operated distributing plate and rotating means, .means comprising a a A source of liquid and a distributor for covering the inner surface of said screen with a washing fluid and mechanical means for removing food stuffs from the exterior surface of said screen, comprising a brush member associated with said mechanical distributing device.

8. An irradiating device comprising a funnel shaped chamber member, an arc lamp containing flame carbon electrodes positioned approximately at the axis thereof, a distributor member positioned at the top of said funnel shaped chamber com rising a plate member and means for pro ucing rotation thereof, Asaid plate member being slightly smaller than the top of said chamber, means within said cone vfor the tumbling of substances during passage therethrough, and means for the collection thereof at the bottom of said chamber.

In testimony whereof, I aiiix my signature.

NEWCOMB K. CHANEY.

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